SQL predicates, also referred to as logical predicates, are types of conditional expressions. They specify a condition of a row or group that has one of three possible states:
- NULL (or unknown)
Predicates can appear in the following:
- WHERE, ON, or HAVING clause to qualify or disqualify rows in a SELECT statement.
- WHEN clause search condition of a searched CASE expression.
- CASE_N function.
- IF, WHILE, REPEAT, and CASE statements in stored procedures.